Medical imaging equipment having a conveying device that is movable in at least one direction is already known. The medical imaging equipment, by way of example a magnetic resonance tomography apparatus, a computerized tomography apparatus and/or a PET apparatus, is very accurate and this requires precise determination of a position of the conveying device in order to be able to carry out a treatment and/or an examination. In this connection a patient is moved into a receiving region of medical imaging equipment by means of the conveying device, the conveying device preferably comprising a mobile patient couch which is arranged so as to be movable in at least one direction. The medical imaging equipment comprises a position-detecting device for detecting the position of the movable conveying device.
In a conventional position-detecting device a position of the conveying device is detected by means of an encoder which is arranged in a drive unit of the conveying device and/or is coupled thereto. However, there is a great inaccuracy in the detected position of the conveying device with this method.
A further known position-detecting device comprises thread take-ups which are also moved as the conveying device is moved. This movement of the thread take-ups is detected and the position of the conveying device determined therefrom. However, this method has the drawback that owing to an elasticity and/or a stretching of a material of the thread take-ups the detected position of the conveying device is highly inaccurate.
A position-detecting device comprising optical sensors and/or controllers for determining and/or detecting a movement and/or position of the conveying device is also known. However, this method has the drawback that these sensors and/or controllers are arranged at least partially within the receiving region and are therefore exposed to treatment and/or examination radiation. This can undesirably impair both treatment and position detection.
A further known position-detecting device of medical imaging equipment, moreover, comprises a laser system which includes a laser source for emitting a laser signal and a detector element for receiving the laser signal. The laser signal is beamed directly from the laser source onto the detector element in this case. Conventional measuring methods, such as a time of flight method by way of example, are very imprecise in terms of position detection, however. Furthermore, the laser source and/or the detector element are arranged on the movable conveying device and are therefore exposed to examination radiation.